I have two groovy scripts A and B.
A looks like:
import some.Class
//Some helper function
String doSomeWork(Integer input) {
//does something with input and returns a String
return "result: $input"
}
//Now do some real stuff here
println( doSomeWork(42) )
In B I want to import A (its in the classpath) and use its doSomeWork:
import A
println A //prints class A. This means we can access it here. =)
println( A.doSomeWork(45) ) //Now try to call As doSomeWork
The last line however results in an exception:
Caught: groovy.lang.MissingMethodException: No signature of method: static A.doSomeWork() is applicable for argument types: (java.lang.Integer) values: [45]
Possible solutions: doSomeWork(java.lang.Integer)
groovy.lang.MissingMethodException: No signature of method: static A.doSomeWork() is applicable for argument types: (java.lang.Integer) values: [45]
Possible solutions: doSomeWork(java.lang.Integer)
at B.run(B.groovy:3)
import A //Will execute As code
println A //prints class A. This means we can access it here. =)
println( (new A()).doSomeWork(45) ) //Now call As doSomeWork
What do I have to do to successfull call As doSomeWork in script B?
EDIT: Okay, I found out. it is not a static method but a method of A. So (new A()).doSomeWork(45) is doing the job. However, that means when A is imported, all its code is executed before Bs code. How can I avoid that? My goal is to only use As method (which obvioulsy does not access any of As properties) without A doing any other side effects.
Related
I am trying to evaluate string as code in groovy and it is failing with groovy.lang.MissingMethodException exception even though method exists in the same script. As I understood groovy runs new instance every time it tries to evaluate the code, but is there any way to inject current script into Eval.me or GroovyShell().evaluate() so that it can find the method and runs it ?
Below is sample code snippet,
def justSayHello(){
return "hello"
}
def my_str = "justSayHello()"
//Eval.me(my_func_str)
new GroovyShell().evaluate(my_func_str)
Both Eval and GroovyShell().evaluate() are throwing below exception
Caught: groovy.lang.MissingMethodException: No signature of method: Script1.justSayHello() is applicable for argument types: () values: []
groovy.lang.MissingMethodException: No signature of method: Script1.justSayHello() is applicable for argument types: () values: []
at Script1.run(Script1.groovy:1)
at string_split.run(string_split.groovy:35)
The following code:
justSayHello = {
println "hello"
}
def my_str = "justSayHello()"
new GroovyShell(binding).evaluate(my_str)
prints out hello when run. Here we have changed justSayHello from a method (on an implicit class that you can not see but which the groovy compiler generates around your script) to a closure. Further we are not doing def justSayHello as that would be defining it as a field on the implicit surrounding class (again which you can't see, but it's there), but rather just defining the variable without any modifiers which puts it in the global binding of the script.
We then send in the binding to the GroovyShell so that it can find the variable.
Result:
─➤ groovy solution.groovy
hello
A more generic variant is to do something like this:
def justSayHello() {
println "hello"
}
def someOtherMethod() {
println "hello again"
}
def methods = this.class.declaredMethods.findResults { m ->
if (m.name.startsWith('$') || m.name in ['main', 'run']) return null
[m.name, this.&"${m.name}"]
}.collectEntries { it }
// just for debugging, print the methods
methods.each { k, v ->
println "method: $k"
}
def my_str = "justSayHello()"
new GroovyShell(new Binding(methods)).evaluate(my_str)
which prints:
─➤ groovy solution.groovy
method: justSayHello
method: someOtherMethod
hello
here we find all the declared methods in the implicit class generated by groovy, remove some stuff added by the groovy compiler (namely main, run and methods starting with a $) and then send the resulting map as the binding for the GroovyShell constructor.
I suspect there might be a more elegant way of accomplishing this, so any groovy gurus - feel free to correct me here.
For an explanation of the implicit enclosing class for a groovy script, see for example this stackoverflow answer.
I'm trying to test my Kotlin code, which has Arrow-kt types, using Spock in Groovy. However, I'm not able to use Arrow-kt's additions such as Some. For example, I have a test as follows:
#Unroll
def "add returns #expected for queryRecord #queryRecord"() {
given:
def ip = "ip"
def rule = "rule"
when:
def result = unit.add(ip, rule)
then:
1 * dynamoDBMapperMock.load(ActionRecord.class, ip) >> queryRecord
result == expected
where:
queryRecord | expected
new ActionRecord() | None.INSTANCE
null | Some(new ActionInternal("ip"))
}
While the first data row succeeds with no problems, the second one fails with the following error:
groovy.lang.MissingMethodException: No signature of method: package.name.EventSpec.Some() is applicable for argument types: (package.name.ActionInternal) values: [ActionInternal(dropletIp=null)]
Possible solutions: Mock(), Spy(), Stub(), dump(), Mock(groovy.lang.Closure), Mock(java.lang.Class)
I've tried .some() as well, but not to avail. Apparently Groovy can't access Kotlin extensions, but Some is simply a data class[1], so I'm not sure why I cannot use it in Groovy.
Yes, you can use Arrow Datatypes in Groovy, the result is not as idiomatic as in Kotlin because the library heavily depends on extension functions and functions in the companion object
Example
import arrow.core.Option
import static arrow.core.OptionKt.getOrElse
static main(args){
println 'What is your name?'
def name = Option.#Companion.fromNullable(System.in.newReader().readLine())
.filterNot { it.isEmpty() }
.map { it.toUpperCase() }
println("Welcome ${getOrElse(name) { 'Anonymous' }}")
}
Output
'Welcome JOHN' (or 'Welcome Anonymous' if the provided name is null or empty)
As you can see, to be able to use getOrElse extension function, we need to import it as a static method
Hint
Do not use Some directly unless you are absolutely sure the value is not null, otherwise, you should rely on Option.fromNullable to safely lift the value to the Option context (i.e create Some or None depending if the value is null or not)
I am trying to parse through some properties file using configslurper.
ENT.adminserver.nodenumber=1
ENT.managedserver.1.host=vserver04
ENT.managedserver.2.host=vserver05
ENT.managedserver.3.host=vserver08
ENT.managedserver.4.host=vserver07
Said properties file. I am trying to read the host names from the properties.
Properties properties = new Properties()
File propertiesFile = new File('DomainBuild.properties')
propertiesFile.withInputStream {properties.load(it)}
def config = new ConfigSlurper().parse(properties)
def domainname="ENT" //will be passed through paremeters
def domain = config.get(domainname)
def managedServerFlow= {
println domain.managedserver
println domain.managedserver.keySet()
domain.managedserver.each {
println it.getClass()
println it.get("1")
}
for (server in domain.managedserver) {
println server.getClass()
println server
}
}
}
the it.get("1") is causing the following error.
No signature of method: java.util.LinkedHashMap$Entry.get() is applicable for argument types: (java.lang.String) values: [1]
Possible solutions: getAt(java.lang.String), grep(), grep(java.lang.Object), wait(), getKey(), any()
I looked through the java and groovy doc and spent few hours without resolution. Please help.
Instead of
println it.get("1")
Try
println it.'1'
Or
println it.getAt("1") // as the exception shows you
Think about what types you are working with. config is a ConfigObject, which you can treat like a map. Its sub-objects domain and domain.managedserver are also ConfigObjects. When you call each on domain.managedserver and pass it a closure that takes no parameters, it gives you a set of Entries. Therefore you can't call it.get("1") because an Entry doesn't have a property called "1". It has key and value. So you can either println "$it.key: $it.value" or
domain.managedserver.each { key, value ->
println value.getClass()
println "$key: $value"
}
or if you want to get the value for key "1" directly:
println domain.managedserver.'1'
I am trying to run a basic example for the Geb library (http://www.gebish.org/manual/current/intro.html#introduction). Here is the code:
import geb.Browser
Browser.drive {
go "http://google.com/ncr"
// make sure we actually got to the page
assert title == "Google"
// enter wikipedia into the search field
$("input", name: "q").value("wikipedia")
// wait for the change to results page to happen
// (google updates the page dynamically without a new request)
waitFor { title.endsWith("Google Search") }
// is the first link to wikipedia?
def firstLink = $("li.g", 0).find("a.l")
assert firstLink.text() == "Wikipedia"
// click the link
firstLink.click()
// wait for Google's javascript to redirect to Wikipedia
waitFor { title == "Wikipedia" }
}
When I try to run this (using Eclipse's groovy support) I get the following exception:
Caught: groovy.lang.MissingMethodException: No signature of method: static geb.Browser.drive() is applicable for argument types: (ExampleScript$_run_closure1) values: [ExampleScript$_run_closure1#2a62610b]
Possible solutions: drive(groovy.lang.Closure), drive(geb.Browser, groovy.lang.Closure), drive(geb.Configuration, groovy.lang.Closure), drive(java.util.Map, groovy.lang.Closure), print(java.lang.Object), print(java.io.PrintWriter)
groovy.lang.MissingMethodException: No signature of method: static geb.Browser.drive() is applicable for argument types: (ExampleScript$_run_closure1) values: [ExampleScript$_run_closure1#2a62610b]
Possible solutions: drive(groovy.lang.Closure), drive(geb.Browser, groovy.lang.Closure), drive(geb.Configuration, groovy.lang.Closure), drive(java.util.Map, groovy.lang.Closure), print(java.lang.Object), print(java.io.PrintWriter)
at ExampleScript.run(ExampleScript.groovy:21)
I think this is saying that the closure I am passing to the static Browser.drive method is not type compatible with groovy.lang.Closure, but I don't know why. Simple groovy hello world scripts work fine but passing a closure to a method always returns a similar error.
Plagiarized from: http://groovy.codehaus.org/Differences+from+Java
Java programmers are used to semicolons terminating statements and not having closures. Also there are instance initializers in class definitions. So you might see something like:
class Trial {
private final Thing thing = new Thing ( ) ;
{ thing.doSomething ( ) ; }
}
Many Groovy programmers eschew the use of semicolons as distracting and redundant (though others use them all the time - it's a matter of coding style). A situation that leads to difficulties is writing the above in Groovy as:
class Trial {
private final thing = new Thing ( )
{ thing.doSomething ( ) }
}
This will throw a MissingMethodException!
groovy Singleton (NB at Groovy 2.6 you must set strict to false if you want to include the explicit constructor)
#Singleton( strict = false )
class test {
private test(){
//some Method call
}
private test(def x){
//some Method call
}
}
test.groovy
def test1 = test.instance
when i issue the following statement it works for me and i can see the defualt
constructor is called
how can i create instanace while using second construcor argument
if i issue
def test2 = test("anish").instance
it throws me error how do i resolve this any suggestion
groovy.lang.MissingMethodException: No signature of method: test.test() is applicable for argument types: (java.lang.String) values: [anish]
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:54)
at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:78)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:44)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:143)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:151)
In the first case you are accessing the static property test.instance, which in turn calls the static method test.getInstance(). In the second case, it looks like you are trying to call the second constructor as a method. That's not valid groovy: you need to use the new keyword to create an instance, which triggers the constructor. Also, making the constructor private makes it inaccessible except within the class itself.
If you need to instantiate another instance, it probably shouldn't be a singleton in the first place.